Process of heat treating steel



Piaten'ted Deel mg LEABABbN W. meme, me ewrveeemi, mi eeeieee BAND, ome, .eeseimee we 'freie www A wBPoReefioN/ce eme.

v eze-'weefse- H This invention 'weleees be the gecese 'ef treating steei Whicii'ie to be eubjeceeci '27e heet.

treatment in en electric furnace and geeft-icm .-larly 'to an improved. method of heet weet# y will be rapidly worn ewejv when the aritmie .ing steei gears and jsimiier articles having hardened machined empieces,

It has been found. the?, eizeei eiicies auch as gears which heveaeem iie'e; im n eiectrieiuriiece me Teez'eiy ffffei" en Vtheiouei smecee-theiji :imi/i Vee heet in gas fired or'oii *wiping "xe-cee, @This softened surface cemci'ion eee me oce'ei in 'gasend eii fuedurimcee ee ehe eeeiiemeee'ee aises to which Lime geeis "eueje .eci il eeelng heet treement peeeeT/e the emi? teni', of the eeei.-

"the eieetw air the oxygen in. which. decemmii. e he outer" eirfece @if the geerte.' e fiepii ei'ceeii ing the commercial and; grimieg alowenice usueiiy empioyefi in meeiiiiie s'e'p factice. The )result of this ieieeeiiou's eine ace decm'bonizetion is time .shape oi @he 'tooth or weei'iilg fece e ehe arisicie which has been' so carefuiiy oesigned ifesrmec is put into service uniees, im. iie menui'ee' ture, a suqclent amount of nd'mg ei me chinng stock is allowed to essere remcve of the .seftenedsurfece The iezexc @factice obvlously increases the 'prcduceien ilmeheiid costv and furthermore, is uncertain of Teenie 'as `there is Ano un'ifomofiiy` in the ieptii ef ehe f decarbomzetion. i l

' For-mstence m a cam o3? irreguiei ioi'me tion the'most iecticei Grinding' teierence vaccording to the particular design, may iie five .thousmldths of en inch enfui thiemey be an adequa'ee allowance for the mejo: pc'fiicns of the cem, but at the 'peek of the cem, Wiiee the greatest vii'eziiv usueiiy occurs7 iiie s'geei mayl be decarbuiizeci to e riepih of een io twelve theusendths While eli. other sui-faces are only vsoftened one er jwo thousen'hs 'in depth.. Mo'eeve'r there is stili e. iuthef um 'certainty es to what the deph ci the decimi'- bonizationmay be, this variation yresiding in di'ercni aiotments of steel ci" @he same grade wherein some specmeiie'e'fe found to .vary from' fi've to ten thousendthe more than others under` identical ieetmexh i.he object of this invenion s'topioduce steel gears and similar objects which. will @F TREN@ STEEL.

which may be cozrieidered. es i'usretive fee he puijpofs'e oi describing the' invention, is Hirsi; ceibomzeci emi. meehined, then ceetedf with e meeiiei ccemcmized by ies iriipieg m marrying out the'inventiom e steei geez @ieg/ed becomes frese@ iuicieeis the Itegem gee? is eiibieceed paco geen?. some time iateix Ail eempie- @if eueh,

met :il ie sodimm eie. ocreie ci eerie en iiyciie although ohei' materiels or ehe combinetiofi ei various materials having `the beve cimiectei'isce muy be used.

The prefei'ed practice ci applying ziiem'zivteiiei is fo Sabine e the gege m :1. Soin ion 0i we'ei' and bei M which an zaciuice mit ci diemmnceeue e; c inely com mnm'edparticles of sihczimay be added 'ZIO thicken the eoiuion and 'essere athorougii and even coating. 'Yi/imc en eduieiani, 'is employed it has been found adventageeus to maintain this material in suspension by egietin'g the eolueion with u suitabie ea'ir'n ring mechanism -oi by boiling it. A.' solu# and 15% dietomace'ous earth or kieselgulir;

This solution affords not only e heavy impregnabie coating but in addition has 'the Aadvantage cf maintaining its liquefied state 'from dey'to (lay Without appreciable change.

Various modifications may be made in tl'ie Inode of applying the coating or insulating material before l1 at treatment such es dnstingpowdered bo on an article which has been pre-heated the melting point of borax and permitting the boren thus deposived to becoxneliused then `to rotate the article until the surfaces are entirelycoeted. 1This method Wliiieeuccessful on some forms oi Work is not entirely dependable as the powA dered boren fuses so readily that it is apt to iow :may rom the surfaces which are contiguous with the greatest mass of steel.

Another method oi" applying the coating' is to submerge the gear into e molten mixture of boren in which powdered stone or plaster of Paris is held in suspension by any suitable means.

After the gear is coated it may be placed in an electric furnace and heut treated and. quenched. according to the accepted practice for the particular grade of steel employed meteen und theree Jter the coating material may be picklmg describeda but includes all materials having the sume or concomitant qualities, chui-:ic teristics and properties'.

Having 'thus described the invention9 what ie claimed and desired to be secured by Letn ters Peten@ is:

l. The composition for preventing deca@ bonizution While lient treating comprising 55 percent Water, 15 percent kieselguhrand 30 percent boren.

2. A composition y.for preventing deemn lionization during lient treatment consisting entirely of kiesclguhr, Water, and boi-21X.,

3. A composition for preventing (leentY benization during lient treatment comprising Substantially one part kieseigulir, two'parts lloran', and ioirrparts Weten,

In testimony whereof We hereunto eiix our signatures this i8th day of. Septeinber i936 Ln "einen "et iitrn'nnr. i Geenen n. nient/nin.

to be understood that the invention not y lnnited t0 the precise mode of applying; the' coating nor to the specific materiels above 

